1. Technical Field
This invention relates generally to circuitry and components for radio controlled (R/C) models, and more particularly to an R/C speed controller with increased functionality and improved ergonomic features.
2. Description of Related Art
The battery powered drive motor of a conventional R/C model operates under control of a control system that includes an onboard speed control module (or R/C model speed controller), a miniature onboard receiver, and a separate handheld transmitter unit. A user manipulates a throttle/brake trigger on the transmitter unit to input speed and braking setpoint information. The transmitter unit communicates that information to the speed controller via the onboard receiver. The speed controller controls the drive motor accordingly.
An existing speed controller includes an electronic circuit that is adapted (i) to be mounted on an R/C model, (ii) to be connected to a battery, a motor, and a receiver on the R/C model, and (iii) to couple power from the battery to the motor according to speed and braking information received via the receiver. The electronic circuit may include a preprogrammed controller that is an electronic device adapted to control operation of the electronic circuit under program control according to a stored setting for each of a group of operating parameters. The parent application (Ser. No. 09/152,372) describes an R/C model speed controller circuit with two pushbutton switches and a front panel row of at least four light-emitting elements that cooperate with the preprogrammed controller to significantly facilitate the task of changing operating parameters. The user simply actuates the pushbutton switches while viewing information displayed by the row of light-emitting elements. That is done without having to manipulate potentiometers while viewing a separate meter connected to a test point on the speed controller and without having to enter data and commands via a miniature keypad.
A separate problem not addressed in the parent application relates to flyback current. Whenever the motor is turned off, the motor's collapsing magnetic field combined with other motor attributes produces a flyback current in a known way that flows through the a flyback diode in the brake circuit of the speed controller. The power dissipated by the flyback diode can be significant to an R/C enthusiast bent on obtaining maximum efficiency and use of limited battery power. Thus, such R/C enthusiasts need a more efficient flyback circuit than currently existing in R/C speed controllers.